Skip to main content

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Downmixing options in AC3 Machine (Read 4094 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Downmixing options in AC3 Machine

Can anyone explain what each of the Azid Downmix Levels options in AC3 Machine do? What should I set them to if I just want to keep the exact same settings as the original 5.1 AC3 (taken straight off the DVD) but just at a lower bitrate?

Also, how low can I encode the AC3 in 5.1 without the quality getting too bad (ie keeping quality roughly equivalent to say a 128 abr mp3 in lame or to a q2 vorbis file?). Is 256 reasonable?

Would I be better off using AAC instead (I'm doing this to use as the sound in a DivX movie)?

Downmixing options in AC3 Machine

Reply #1
Quote
Originally posted by The Belgain
Also, how low can I encode the AC3 in 5.1 without the quality getting too bad (ie keeping quality roughly equivalent to say a 128 abr mp3 in lame or to a q2 vorbis file?). Is 256 reasonable?


If you want high quality AC3 encoding, you will probably need a commercial AC3 encoder, like SonicFoundry's SoftEncode and Surcode Dolby Digital. And I think a 5.1 AC3 at 256kbps will sound quite worse than a MP3 at 128kbps (Although a stereo AC3 should sound better)

Quote
Would I be better off using AAC instead (I'm doing this to use as the sound in a DivX movie)?


Yes, but, unfortunately, there are no good AAC DirectShow filters yet.

Regards;

Roberto.

 

Downmixing options in AC3 Machine

Reply #2
Quote
Originally posted by The Belgain
Can anyone explain what each of the Azid Downmix Levels options in AC3 Machine do? What should I set them to if I just want to keep the exact same settings as the original 5.1 AC3 (taken straight off the DVD) but just at a lower bitrate?
[/b]simply select "5.1".

Quote
Would I be better off using AAC instead (I'm doing this to use as the sound in a DivX movie)?
quality of AacEnc is most probably better, but encoding to aac will prevent you from being able to play your movie thru spdif.